diff options
Diffstat (limited to 'third_party/git/xdiff/xhistogram.c')
| -rw-r--r-- | third_party/git/xdiff/xhistogram.c | 384 |
1 files changed, 0 insertions, 384 deletions
diff --git a/third_party/git/xdiff/xhistogram.c b/third_party/git/xdiff/xhistogram.c deleted file mode 100644 index c7b35a9667f3..000000000000 --- a/third_party/git/xdiff/xhistogram.c +++ /dev/null @@ -1,384 +0,0 @@ -/* - * Copyright (C) 2010, Google Inc. - * and other copyright owners as documented in JGit's IP log. - * - * This program and the accompanying materials are made available - * under the terms of the Eclipse Distribution License v1.0 which - * accompanies this distribution, is reproduced below, and is - * available at http://www.eclipse.org/org/documents/edl-v10.php - * - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or - * without modification, are permitted provided that the following - * conditions are met: - * - * - Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * - Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following - * disclaimer in the documentation and/or other materials provided - * with the distribution. - * - * - Neither the name of the Eclipse Foundation, Inc. nor the - * names of its contributors may be used to endorse or promote - * products derived from this software without specific prior - * written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND - * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, - * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR - * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; - * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER - * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, - * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF - * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -#include "xinclude.h" - -#define MAX_PTR UINT_MAX -#define MAX_CNT UINT_MAX - -#define LINE_END(n) (line##n + count##n - 1) -#define LINE_END_PTR(n) (*line##n + *count##n - 1) - -struct histindex { - struct record { - unsigned int ptr, cnt; - struct record *next; - } **records, /* an occurrence */ - **line_map; /* map of line to record chain */ - chastore_t rcha; - unsigned int *next_ptrs; - unsigned int table_bits, - records_size, - line_map_size; - - unsigned int max_chain_length, - key_shift, - ptr_shift; - - unsigned int cnt, - has_common; - - xdfenv_t *env; - xpparam_t const *xpp; -}; - -struct region { - unsigned int begin1, end1; - unsigned int begin2, end2; -}; - -#define LINE_MAP(i, a) (i->line_map[(a) - i->ptr_shift]) - -#define NEXT_PTR(index, ptr) \ - (index->next_ptrs[(ptr) - index->ptr_shift]) - -#define CNT(index, ptr) \ - ((LINE_MAP(index, ptr))->cnt) - -#define REC(env, s, l) \ - (env->xdf##s.recs[l - 1]) - -static int cmp_recs(xpparam_t const *xpp, - xrecord_t *r1, xrecord_t *r2) -{ - return r1->ha == r2->ha && - xdl_recmatch(r1->ptr, r1->size, r2->ptr, r2->size, - xpp->flags); -} - -#define CMP_ENV(xpp, env, s1, l1, s2, l2) \ - (cmp_recs(xpp, REC(env, s1, l1), REC(env, s2, l2))) - -#define CMP(i, s1, l1, s2, l2) \ - (cmp_recs(i->xpp, REC(i->env, s1, l1), REC(i->env, s2, l2))) - -#define TABLE_HASH(index, side, line) \ - XDL_HASHLONG((REC(index->env, side, line))->ha, index->table_bits) - -static int scanA(struct histindex *index, int line1, int count1) -{ - unsigned int ptr, tbl_idx; - unsigned int chain_len; - struct record **rec_chain, *rec; - - for (ptr = LINE_END(1); line1 <= ptr; ptr--) { - tbl_idx = TABLE_HASH(index, 1, ptr); - rec_chain = index->records + tbl_idx; - rec = *rec_chain; - - chain_len = 0; - while (rec) { - if (CMP(index, 1, rec->ptr, 1, ptr)) { - /* - * ptr is identical to another element. Insert - * it onto the front of the existing element - * chain. - */ - NEXT_PTR(index, ptr) = rec->ptr; - rec->ptr = ptr; - /* cap rec->cnt at MAX_CNT */ - rec->cnt = XDL_MIN(MAX_CNT, rec->cnt + 1); - LINE_MAP(index, ptr) = rec; - goto continue_scan; - } - - rec = rec->next; - chain_len++; - } - - if (chain_len == index->max_chain_length) - return -1; - - /* - * This is the first time we have ever seen this particular - * element in the sequence. Construct a new chain for it. - */ - if (!(rec = xdl_cha_alloc(&index->rcha))) - return -1; - rec->ptr = ptr; - rec->cnt = 1; - rec->next = *rec_chain; - *rec_chain = rec; - LINE_MAP(index, ptr) = rec; - -continue_scan: - ; /* no op */ - } - - return 0; -} - -static int try_lcs(struct histindex *index, struct region *lcs, int b_ptr, - int line1, int count1, int line2, int count2) -{ - unsigned int b_next = b_ptr + 1; - struct record *rec = index->records[TABLE_HASH(index, 2, b_ptr)]; - unsigned int as, ae, bs, be, np, rc; - int should_break; - - for (; rec; rec = rec->next) { - if (rec->cnt > index->cnt) { - if (!index->has_common) - index->has_common = CMP(index, 1, rec->ptr, 2, b_ptr); - continue; - } - - as = rec->ptr; - if (!CMP(index, 1, as, 2, b_ptr)) - continue; - - index->has_common = 1; - for (;;) { - should_break = 0; - np = NEXT_PTR(index, as); - bs = b_ptr; - ae = as; - be = bs; - rc = rec->cnt; - - while (line1 < as && line2 < bs - && CMP(index, 1, as - 1, 2, bs - 1)) { - as--; - bs--; - if (1 < rc) - rc = XDL_MIN(rc, CNT(index, as)); - } - while (ae < LINE_END(1) && be < LINE_END(2) - && CMP(index, 1, ae + 1, 2, be + 1)) { - ae++; - be++; - if (1 < rc) - rc = XDL_MIN(rc, CNT(index, ae)); - } - - if (b_next <= be) - b_next = be + 1; - if (lcs->end1 - lcs->begin1 < ae - as || rc < index->cnt) { - lcs->begin1 = as; - lcs->begin2 = bs; - lcs->end1 = ae; - lcs->end2 = be; - index->cnt = rc; - } - - if (np == 0) - break; - - while (np <= ae) { - np = NEXT_PTR(index, np); - if (np == 0) { - should_break = 1; - break; - } - } - - if (should_break) - break; - - as = np; - } - } - return b_next; -} - -static int fall_back_to_classic_diff(xpparam_t const *xpp, xdfenv_t *env, - int line1, int count1, int line2, int count2) -{ - xpparam_t xpparam; - xpparam.flags = xpp->flags & ~XDF_DIFF_ALGORITHM_MASK; - - return xdl_fall_back_diff(env, &xpparam, - line1, count1, line2, count2); -} - -static inline void free_index(struct histindex *index) -{ - xdl_free(index->records); - xdl_free(index->line_map); - xdl_free(index->next_ptrs); - xdl_cha_free(&index->rcha); -} - -static int find_lcs(xpparam_t const *xpp, xdfenv_t *env, - struct region *lcs, - int line1, int count1, int line2, int count2) -{ - int b_ptr; - int sz, ret = -1; - struct histindex index; - - memset(&index, 0, sizeof(index)); - - index.env = env; - index.xpp = xpp; - - index.records = NULL; - index.line_map = NULL; - /* in case of early xdl_cha_free() */ - index.rcha.head = NULL; - - index.table_bits = xdl_hashbits(count1); - sz = index.records_size = 1 << index.table_bits; - sz *= sizeof(struct record *); - if (!(index.records = (struct record **) xdl_malloc(sz))) - goto cleanup; - memset(index.records, 0, sz); - - sz = index.line_map_size = count1; - sz *= sizeof(struct record *); - if (!(index.line_map = (struct record **) xdl_malloc(sz))) - goto cleanup; - memset(index.line_map, 0, sz); - - sz = index.line_map_size; - sz *= sizeof(unsigned int); - if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz))) - goto cleanup; - memset(index.next_ptrs, 0, sz); - - /* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */ - if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0) - goto cleanup; - - index.ptr_shift = line1; - index.max_chain_length = 64; - - if (scanA(&index, line1, count1)) - goto cleanup; - - index.cnt = index.max_chain_length + 1; - - for (b_ptr = line2; b_ptr <= LINE_END(2); ) - b_ptr = try_lcs(&index, lcs, b_ptr, line1, count1, line2, count2); - - if (index.has_common && index.max_chain_length < index.cnt) - ret = 1; - else - ret = 0; - -cleanup: - free_index(&index); - return ret; -} - -static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env, - int line1, int count1, int line2, int count2) -{ - struct region lcs; - int lcs_found; - int result; -redo: - result = -1; - - if (count1 <= 0 && count2 <= 0) - return 0; - - if (LINE_END(1) >= MAX_PTR) - return -1; - - if (!count1) { - while(count2--) - env->xdf2.rchg[line2++ - 1] = 1; - return 0; - } else if (!count2) { - while(count1--) - env->xdf1.rchg[line1++ - 1] = 1; - return 0; - } - - memset(&lcs, 0, sizeof(lcs)); - lcs_found = find_lcs(xpp, env, &lcs, line1, count1, line2, count2); - if (lcs_found < 0) - goto out; - else if (lcs_found) - result = fall_back_to_classic_diff(xpp, env, line1, count1, line2, count2); - else { - if (lcs.begin1 == 0 && lcs.begin2 == 0) { - while (count1--) - env->xdf1.rchg[line1++ - 1] = 1; - while (count2--) - env->xdf2.rchg[line2++ - 1] = 1; - result = 0; - } else { - result = histogram_diff(xpp, env, - line1, lcs.begin1 - line1, - line2, lcs.begin2 - line2); - if (result) - goto out; - /* - * result = histogram_diff(xpp, env, - * lcs.end1 + 1, LINE_END(1) - lcs.end1, - * lcs.end2 + 1, LINE_END(2) - lcs.end2); - * but let's optimize tail recursion ourself: - */ - count1 = LINE_END(1) - lcs.end1; - line1 = lcs.end1 + 1; - count2 = LINE_END(2) - lcs.end2; - line2 = lcs.end2 + 1; - goto redo; - } - } -out: - return result; -} - -int xdl_do_histogram_diff(mmfile_t *file1, mmfile_t *file2, - xpparam_t const *xpp, xdfenv_t *env) -{ - if (xdl_prepare_env(file1, file2, xpp, env) < 0) - return -1; - - return histogram_diff(xpp, env, - env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1, - env->xdf2.dstart + 1, env->xdf2.dend - env->xdf2.dstart + 1); -} |